Headlight



A. AMES, JR.

HEADLIGHT.

APPLICATION FILEU DEC. 4. 1917.

Patented Feb. 8, 1921.

UNITED STATESIPATENT OFFICE.

ADELBERT .13., or 'rEwx'sBU'rtY, MASSACHUSETTS.

. HEADLIGHT.

Laoacsz.

Specification of Letters Patent.

Patented Feb. 8, 1921.-

Application filed December 4, 1917. Serial No. 205,428;

their axes without projecting blinding or glaring light-above the horizontal.

The principal objects of the invention are thoroughly to illuminate the roadway without producing upward glare, and to utilize substantially all of the light from the light source instead of intercepting and absorbing a portion as has been proposed. Corrolarial objects are to attain the aforesaid principal objects by means which are simple and economical in construction, which may be applied to headlamps in the most convenient and practical manner, which may be mounted inside the transparent front covers of headlights, and which afford other advantages hereinafter referred to.

To the end of attaining these objects I provide an auxiliary reflector over the upper portion of the front opening of the main reflector so as to reflect the light incident thereto to the main reflector. atsuch angles as to be projected in or below a horizontal direction. The invention consists in shaping and positioning the auxiliary reflector in a critical manner and also'in correlating the various characteristics of the main and auxiliary reflectors in a unique manner. For example, the curvature of the auxiliary reflector and the focal length and axial depth of the main reflector all have a novel relationship to each other.

In the accompanying "drawings which are chiefly diagrammatic,

Figure 1 is a vertical central-section through the preferred embodiment of the present invention, showingthe action, of the auxiliary reflector on the light directly incident thereto;

Fig. 2 is a view similar to Fig. 1 showing the action of the auxiliary reflector on'the light reflected to the auxiliary reflector by the main reflector;

Fig. 3 is a diagram showing the effect on the iight directly incident to the auxiiiaiy reflector, of making the auxiliary reflector too flat;

F 4 is a diagram showing the effect on the llght reflected by the main reflector to the auxiliary reflector, of making the auxiliary reflector too flat, I

Fig. 5 is :1V diagram showing the effect, on the hght directly incident to the auxiliary reflector, of making the curvature of this reflector too great; and

'Fig. 6 is a diagram showingthe effect, on

light reflected from the niain reflector to the auxiliary reflector, of making the curvature of the auxiliary reflector too great.

The preferredembodiment of the present invention illustrated in Figs. 1 and 200mprises a. main reflector P, a light source L in the rear of the focus f of the main reflector P, and an auxiliary reflector A covering substantially the upper halfof the front opening of the main reflector P. While anytype of reflector adapted to project a concentrated beam of light may be employed as the main reflector, I preferably provide a paraboloidal reflector as illustrated. flector A is preferably spherical, at least throughout its upper portion, and the center of curvature of reflector A is preferably in the region of the axis of the main reflector, Well in the rear of the main reflector. In Figs. 1. and .2 I have shown the auxiliary reflector as being spherical throughout its entire area and as having its center of curvature in the axis of the main reflector far in the rear of the main reflector.

I The light source may be variously posi tioned in the region of the focus of the main reflector P but I preferably position it immediately behind the focusas illustrated. When so positioned the light radiating to the lower half of the reflector P is projected in or below a horizontaldirection inasmuch as it radiates either directly from or from behind thefocus. However, with the-light source so positioned the light radiating to the upper half of the main" reflector P is reflected somewhat above the horizontal inasmuch as it comes from behind the focus. If this light is permitted tobe projected from the headlight it would cause upward glare, but with the auxiliary device A this light is intercepted and hence not permitted to pro ject upwardly. By making the inner surface of the reflector A reflecting this intei= cepted light is not wasted but is returned to the main reflector in such manner as to be The auxiliary re-- v positioning the reflector A in the unique manner hereinafter described the intercepted light is caused to be projected in orbelow a horizontal direction so as not to produce upward glare.

In order to cause the light incident to the auxiliary reflec'tor to be returned to the main reflector at such angles as to be projected in or below a horizontal direction through the lower opening the auxiliary reflector must have a critical degree of curvature defined by certain limits in both directions, that is, the curvature must be neither too slight nor too great. If the curvature is too slight some of the light incident to the auxiliary reflector will be projected upwardly while if the curvature is too great the same trouble will be experienced.

In Figs. 3 and 4 I have illustrated the fact that upward glare will result from making the auxiliary reflector too flat and in order more forcibly to illustrate this fact I have shown the auxiliary reflector as hav ing a zero degree of curvature, that is, as being entirely flat.

the light source L, to point 2 on the lower portion of the flat auxiliary reflector A is reflected upwardly to the point 3 on the main reflector and thence downwardly as indicated. Such rays do not give rise to upward glare. However, a ray of light, such as ray 6, radiating to point '4 on the upper portion of the'auxiliary reflector is reflected to point 5 on. the main reflector, thence back to point 6 on the auxiliary reflector, thence 'to point 7 on the main reflector and thence.

upwardly. Such rays give rise to upward glare. Referring to Fig. 4, the ray C 'radi ating fromthe light source L to point 8 on the main reflector is reflected to point 9 on the auxiliary reflector, thence to point 10 on'the main reflector, thence to point 11 on the main reflector and thence upwardly, as indicated. Thus, Fig. 3 shows that a part of the light radiating directly to an auxiliaryreflector which is too flat will be projected upwardly and F ig. 4 shows that a portion of the light reflected from the main reflector to an auxiliary reflector which is too .flat will be projected upwardly.

Referring to Fig. 5 in which the curvature of the auxiliary reflector is too great to produce the desired results, a rayof light 03 radiating to point 12 on the upper portion of the auxiliary reflector is reflected to point 13 on the main reflector and thence upwardly. Likewise, a ray 6 emanating directly to a point 14 lower down on the auxiliary reflector is reflected to point 15 on the main reflector and thence is projected upwardly. In Fig. 6, which is similar to Fig. 5, a ray of light 9 emanating from the Referring particularly to Fig. 3, a ray of light a emanating from light source to point 16 on the main reflector is reflected to point 17 on the auxiliary reflector, thenceto point 18 on the main reflector and thence upwardly. Likewise, a ray h emanating to point 19 on the main reflector is reflected to point 20 on the auxiliary reflector, thence to point 21 on the main reflector and thence upwardly. All rays such as c, d, g and it give rise to upward glare and Figs. 5 and 6 therefore illustrate the effect, on the'direct and reflected light respectively, of making the curvature of the auxiliary reflector too great.

With the auxiliary reflector shaped the proper amount as illustrated in Figs. 1 and 2, a ray of light 11 emanating to a point 22 on the lower portion of the auxiliary reflector is reflected to point 23 on the main reflector and thence downwardly. A ray of light is radiating to point 24 somewhat above the point 22 is reflected'to point 25 on the main reflector and thence downwardly through the opening below the auxiliary reflector. Likewise, a ray Z radiating to point 26 at the top of the auxiliary reflector is reflected to point 27 on the main reflector and thence downwardly through the front opening of the headlight.

Referring to Fig. 2, a ray m radiating from the light source L to the point 28 on the main reflector is reflected substantially horizontally to the point 29 on the lower portion of the auxiliary reflector, thence to point 30 on the main reflector and thence downwardly through the front opening of the reflecton. A ray n emanating to point 31 at the top of the main reflector is reflected to point 32 on the auxiliary reflector, thence successively to points 33, 34 and 35 on the main reflector and thence downwardly through the front opening of the headlight. If other rays be drawn to other parts of the reflectors, either first to the main reflector as in Fig. 2 or first to the auxiliary reflector as in Fig. 1, it will be found that they will be projected in or below a horizontaldirection.

Thus it appears that all light reflected downwardly from the upper half of the main reflector or from the auxiliary reflector to the lower half of the main reflector so as to pass in front of the focus is projected upwardly. It further appears intermediate portions of the roadway while the light projected approximately horizontally from the lower half of the main reflector serves to illuminate the distant portions of the roadway.

The curvature of the auxiliary reflector depends upon several factors, the chief of which are the focal length of the main reflector and the axial depth of the main reflector. Vhile the exact limits between which the curvature of the auxiliary reflector may be varied without-producing upward glare cannot be stated forall conditions, the following examples may be given as illustrating the order of the respective values: First, focal length 1% inches, axial depth 3% inches, distance between the focus of the main reflector and the center of curvature of the auxiliary reflector 9% inches; secondly, focal length 1.

inches, axial depth 3% inches, distance be-- tween focus and center of curvature 14: inches.

The radius ,of curvature of the auxiliary reflector should be sufliciently short to afford a degree of curvature great enough to reflect light that strikes it after reflection to pass behind the focus. On the other hand the auxiliaryreflector should be sufficiently flat tends rearwardly of the focus. The curvature should be such that light emanating from the rearmost point of the light source to the main reflector and thence reflecting to the auxiliary reflector is deflected back so as to pass through or behind the focus' Such rays strike the lower half of the main reflector as if emanating directly from the light source and are thereforeprojected substantially horizontally so as to add to the illumination-of the distant roadway.

While the auxiliary reflector may be mounted in any suitable manner in so far as the inventionin itsbroader aspect is concerned, as for example as a coating of silver on the inner surface of a concave front cover, it is preferably formed as a separate and detachable part which will fit into standard headlights. To this end it .is preferably provided with a flange 36 fitting against the main reflector and with a second flange 37 bent outwardly over the forward flange 39 of the main reflector. A groove 38 is ordinarily provided in the front flange 39 of the headlight and in order to secure the auxiliary reflector in position the flange 37 is preferably made to fit into the groove 38 so that when the front cover is secured to the flange 39 the auxiliary reflector will trated beam of light to the distant roadway be gripped between the flange 39 and the front cover.

In the claims I have employed the term paraboloidal to designate a reflector adapt ed to project a concentrated beam of light along its axis.

I claim l 1. A non-glare headlight comprising a main reflector adapted to project a concenand an auxiliary reflector covering theupper portion of the front opening of the main reflector, the auxiliary reflector facing the main reflector so as to reflect light thereto and having its focus disposed in the region of the axis of the main reflector and behind the main reflector whereby all of the light reflected to the main reflector by the auxiliary reflector is projected to the nearer roadwayand both the distant and nearer portions of the roadway may be adequately illuminated without producing upward glare,

*2. A nonglare headlight comprising a paraboloidal reflector adapted to, project light to the distant roadway and a spherical reflector covering substantially the upper half of the front opening of the paraboloidal reflector, the spherical reflector facing the paraboloidal reflector so as to reflect light thereto and having its center of curvature disposed rearwardly of the focus of the paraboloidal reflector at such distance that the light reflected by the spherical reflector to the paraboloidal reflector will pass in the rear of the focus of the paraboloidal reflector and be uniformly distributed throughout the portion of the roadway between the headlight and the distant illumination of the paraboloidal reflector.

3. A non-glare headlight comprising a main reflector having relatively great curvature and depth so as to extend forwardly of its focus, and an auxiliary reflectorhaving relatively small curvature and depth so as 110 to be disposed in the upper portion of the front opening of the main reflector, the auxiliary reflector facing the main reflector so as to reflect light thereto and having its focus disposed rearwardly of the transverse its focus, an auxiliary reflector having rela- 12C tively small curvature and depth so as to be disposed in the upper portion of the front opening of the main reflector, the auxiliary reflector facing the main reflector so as to reflect light thereto and having its focus disposed rearwardly of the transverse plane of the focus of the main. reflector, and a flan e on the auxiliary reflector adapted to fit a ong the main reflector for securing the auxiliary reflector in position.

5. A non-glare headlight comprising a main reflector having relatively great curvature and depth so as to extend forwardly of its focus, an auxiliary reflector having rel-ttively small curvature anddepth so as to be disposed in the upper portion of the front opening of the main reflector, the auxiliziry reflector facing the main reflector so as to reflect light thereto and having its focus 10 disposed rearwardly of the transverse plane 1,se7,ese

of the focus of the main reflector, and aflange on the outer periphery of the auxiliary reflector adapted to fit between the periphery of the main reflector and the front cover of the headlight for securing the auxiliary reflector in position.

Signedby. me at Fortress Monroe, Va., this twenty-sixth day of November, 1917.

ADELBERT AMES, J R. 

